Ethylene Glycol → 2-(3,4-dichlorophenyl)3H-imidazo[4,5-b]pyridine-3-acetic acid

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Reaction Steps

A mixture of N-[3-[(3,4-dichlorobenzoyl)amino]-2-pyridinyl]glycine ethyl ester (33 g, 0.09 mole) and 167 ml of ethylene glycol was heated at reflux for 11/2 hr. After cooling, potassium hydroxide (8.4 g) in 40 ml of water was added and the reaction mixture was heated at reflux for 1 hr. The solution was filtered to remove yellow insoluble precipitate, the filtrate was diluted with 650 ml of water, and acidified with ethanolic hydrogen chloride. The solid, which formed, was collected by filtration, washed with water, and dried under high vacuum first at 50° C. overnight, then at 70° C. for 21/2 days to give 25.3 g (98%), mp 248°-49° C.

Provenance & Evidence